Hi Lindsey, the Rock Island Armory ROCK Ultra CS-L Combo does not have a rail for adding a laser. The only option I know of is the Crimson Laser grips budsgunshop.com/product_info.php/products_id/156591/crimson+trace+lg+902+1911+master+series+officersdefendercompact+-+rosewood+grip ,
Stay safe & have a great day!

This is a solid choice
budsgunshop.com/product_info.php/products_id/194353/nightstick+tcm10gl+tcm-10-gl+compact+tactical+weapon+light+w+laser+black+for+handguns+650+lumens+white+light+green+laser

Here’s your only option: budsgunshop.com/product_info.php/products_id/156591/crimson+trace+lg+902+1911+master+series+officersdefendercompact+-+rosewood+grip

Based on the Picatinny rail configuration of the Rock Island Armory Rock Ultra CS-L (SKU 56633), which is a compact 1911 with an under-barrel rail, comparable and compatible laser or light/laser combo options include compact, rail-mounted units.
Top Compatible Laser/Light Combos:
Streamlight TLR-7 Sub (1911 Version): A highly recommended compact weapon light (and available light/laser combo) that fits tight rail spaces on 1911 compacts.
Streamlight TLR-6: A popular option for compact handguns, though typically designed for non-railed or proprietary rails, universal versions can fit, but the TLR-7/TLR-8 series is better for true railed frames.
Holosun RML Series: Rail-mounted laser units that are compact and robust.
Olight Baldr Mini: A compact, magnetic-charging light and laser combo that fits under-barrel rails.
TruGlo Tru-Point Laser/Light Combo: Often used on RIA pistols for a budget-friendly rail option.

budsgunshop.com/product_info.php/products_id/12812/crimson+trace+lasergrip+for+1911+officerdefender />budsgunshop.com/product_info.php/products_id/156591/crimson+trace+lg+902+1911+master+series+officersdefendercompact+-+rosewood+grip

Good evening to you!! See below link for more information.
budsgunshop.com/product_info.php/products_id/156591/crimson+trace+lg+902+1911+master+series+officersdefendercompact+-+rosewood+grip ---
budsgunshop.com/product_info.php/products_id/12812/crimson+trace+lasergrip+for+1911+officerdefender

Hi Lindsey and welcome. Although expensive, the Crimson Laser Grips: budsgunshop.com/product_info.php/products_id/156591/crimson+trace+lg+902+1911+master+series+officersdefendercompact+-+rosewood+grip ---------- would work. Cheers and stay safe!